Connection of discharge electrodes

ABSTRACT

An electrostatic precipitator has vertical discharge electrodes which are restrained from vibration by horizontal connecting members running between the electrodes and interacting with them. The connecting members are secured outside the electric field to end frames of the support structure from which the electrodes hang. The electrodes and the connecting members are capable of relative vertical movement where they interact. One form of connecting member is a taut wire woven through each row of discharge electrodes; in another form an electrode is received in a sleeve passing vertically through a rod-like connecting member. The connecting members are provided at a level or levels not coincident with the expected nodes of standing waves likely to occur in the electrodes.

United States Patent 1191 Heer et a1.

[ CONNECTION OF DISCHARGE ELECTRODES [75] lnventors: Heribert Heer, Olpe-Rhode; Werner Kantelhardt, Olpe; Gerhard Kritzler, Freudenberg, all of Germany [73] Assignee: Apparatebau Rothemuhle Brandt &

Kritzler, Rothemuhle, Germany [22] Filed: Oct. 12,1971 [21] Appl. No.: 188,106

[30] Foreign Application Priority Data June 14,1971 Germany P 21 29 347.0

[52] US. Cl 55/146, 29/517, 55/147, 1 p H 55/148, 55/15 i, 55 l 5 2, 55/153 l izgltlixiiiliiilgir; [58] Field of Search 55/146, 147, 148, 55/150, 151, 152, 140, 153; 29/517 [56] References Cited UNITED STATES PATENTS 1,428,839 9/1922 Fortescue 55/151 X 2,362 316 11 1944 Phillips 55 147 x 2,369,877 2/1945 White 55/148 X 2,660,260 11/1953 Brixius et al 1. 55/146 X 2,852,093 9/1958 Streuber 55/153 X 1111 3,774,372 14 1 Nov. 27, 1973 Primary ExaminerDennis E. Talbert, Jr. Attorney-Armand E. Lackenbach et al.

[57] ABSTRACT An electrostatic precipitator has vertical discharge electrodes which are restrained from vibration by horizontal connecting members running between the electrodes and interacting with them. The connecting members are secured outside the electric field to end frames of the support structure from which the electrodes hang. The electrodes and the connecting membets are capable of relative vertical movement where they interact. One form of connecting member is a taut wire woven through each row of discharge electrodes; in another form an electrode is received in a sleeve passing vertically through a rod-like connecting member. The connecting members are provided at a level or levels not coincident with the expected nodes of standing waves likely to occur in the electrodes.

7 Claims, 5 Drawing Figures United States Patent 1 Beer et al.

[ Nov. 27, 1973 Patented Nov. 27, 1973 3,774,372

2 Sheets-Shoat 2;

III

Inventors f/smmr Hen M94 41 KfiA/TFLIMIPT Gumw Kan-nu MW ZZW 1 CONNECTION OF DISCHARGE ELECTRODES BACKGROUND OF THE INVENTION The invention concerns discharge electrode connections in electrical precipitators. It is particularly concerned with precipitators where collecting electrodes are arranged in rows spaced at equal distances in parallel planes and where discharge electrodes hangcentrally between the collecting electrodes. The discharge electrodes are suspended from an upper supporting frame, which is fixed in an insulated manner, and are loaded by tensioning weights at their lower ends, being retained in parallel and at uniform distances by'means of lower spacing grids which are rigidly connected with the upper supporting frame, out of the electrical field, by means of end guide frames.

In larger-sized electrical precipitators of this design lateral vibrations of the discharge-electrodes may occur above a certain field-height. These are initiated by the passage of the gas current being subjected to the deposition and by reaction from sparking. It is highly desirable to produce a firm connection amongst the discharge electrodes in order to avoid the occurrence of vibrations on these comparatively long and thin strip-type elements.

To try to meet these requirements it is known in the art to design a connection amongst strip-type discharge electrodes which are suspended in parallel, in such manner that at least two of the strip-type discharge electrodes are fixed on each side of a vertically arranged carrier-tube parallel to the direction of flow of gas by means of spacing holding members (German Offenlegungschrift l 929 224). This design requires the.

application of so many carrier-tubes for the holding of the strip-type discharge electrodes that these constructional. involvements will almost equal in weight the rather heavy carrier-frames used hitherto which already, due to deformations because of weight, have led to different tensioning-distances where large field heights were concerned, causing a large reduction in the separation efficiency of the electrical precipitator. More seriously, vibration of the electrodes can occur about the longitudinal axis of the carrier-tube between them so that this latter tends to swing about its own axis.

' Also known in the art is a type of discharge electrode connection where the strip type discharge electrodes are subdivided within the height of the active electrical field into two or more parts of equal length and where the ends between longitudinally consecutive parts of parallel discharge electrodes are fixed to each other at their ends by means of a mutual connection-piece (German Utility Model 7 020 757).

,This multiple subdivision of the discharge electrodes into parts of equal lengths and the arrangement of sevral connecting members in between two parallelrunning, strip-type discharge electrodes at equal heights within that of the electrical field made it possible to suppress sufiiciently all transverse vibrations occurring in electrical precipitator plants of field heights currently in operation.

.In electrical precipitators with very large field heights, however, the suppression of vibrations achieved by means of these known devices can be too small, as that a build-up of vibrations cannot always be prevented. It is also possible that torsional vibrations of the two strip-type discharge electrodes which are connected part the way along their lengths, may occur and this will also have an adverse effect on the performance of the electrical precipitator.

SUMMARY OF THE INVENTION The object of the present invention is therefore to develop a design of spacing holding members for the discharge electrodes with the best amount of material but in such manner that the discharge electrodes are no longer have the tendency to perform substantial vibrational movements.

The present invention is based on the discoverythat vibrational movements may be damped, whatever the length of the discharge electrode, by allowing the electrode'to move axially,"i.e. in the direction of its own length, relative to the connecting members. Previous constructions have had connections between the connecting' members and the electrodes which did not allow this, movement and the energy-absorbing frictional interaction which it involves. To prevent the swinging which is possible with the prior art construction mentioned above the connecting members extend between end frames of the bank of discharge electrodes.

In the invention we providean electrical precipitator wherein a row of discharge electrodes is suspended vertically under tension from an upper carrier, end frames are rigidly secured at the ends of the upper carrier, and

at least one horizontal connecting member extends between and is secured to the end frames and interacts with the discharge electrodes to hold them part way along their length, the discharge electrodes and the connecting member being capable of relative vertical movement.

In one form of the invention, the discharge electrodes areabutted alternatingly on the left and right by means of one or more horizontal longitudinal connections between the guide frames. In another construction they are guided in their vertical movement relative to the horizontal longitudinal connections by means of insulating spacing elements, such as porcelain beads or sleeves.

The connecting member or members are positioned to subdivide the field height approximately equally. However, the build-up of discharge electrode vibrations can be prevented by arranging that the points of interaction between the longitudinal connecting member(s) and the electrodes are arranged away from the likely vibration nodes of stationary waves in the discharge electrodes (i.e. away from the halfor thirdlengths of the discharge electrodes.)

Two embodiments of the invention will now be described with reference to the accompanying drawings, wherein:

FIG. 1 is a front elevation of a first embodiment FIG. 2 is a sectional view on the line ll ll of FIG.

FIG. 3 is an end elevation of the first embodiment, FIG. 4 is a front elevation partly in section, of the second embodiment and FIG. 5 is an end elevation, partly in section, of the second embodiment.

In the first embodiment, discharge electrodes are held with their upper ends in suspension tubes 3 within a carrier 15 of an upper supporting frame 1 and carry at their lower ends tensioning-weights 9, which are spaced by spacing-grids l0.

The electrodes 2 borne by a single carrier 15 form a row parallel to the direction of gas through the precipitator. There is a plurality of such rows, arranged parallel to each other.

Centrally, between adjacent rows of discharge electrodes is a row of collecting electrodes.

The upper supporting frames 1 are firmly supported or suspended in the electrical precipitator by means of insulators. At each end, the upper supporting frames 1 are rigidly connected with the lower spacing-grids by means of braced end guide frames 13. Only the end frame at one end is shown in the drawings.

Connecting members (5,5) for the discharge elec trodes are wires, tubes and bars of conductive or insulating material.

The longitudinal connecting members are arranged parallel to each other at one level, are in the first embodiment held by their ends and spaced along spacing tubes 14, whilst in the second embodiment this spacing is provided by means of angle iron 14'. Any suitable type of member may be used for this purpose.

In the first embodiment the connecting members 5' are taut wires woven between the electrodes so that they lie alternate sides of them (FlG.2). The members 5 have a surface of a nature to prevent the electrodes sliding along them (e.g. being surrounded by porcelain beads) and the electrodes are movable, against friction, vertically relative to the connecting members.

In the second embodiment the connecting member 5 is a tube and the electrodes are vertically movable on these by means of bores, lugs, or (as shown) porcelain guide sleeves ll. Sleeves 11 may be replaced by porcelain beads.

FIGS. 4 and 5 show how the discharge electrodes can be divided along their length. The consecutive parts 2 and 2" of each are of equal length and are inserted in the upper and lower ends respectively of a tube-sleeve 4 and are firmly compressed with it to become crimped to it in known manner at two points 6, 7, which are closely adjacent to each other.

The tube-sleeves 4 are housed within the sleeves l l to restrain the electrodes from vibration. A tube sleeve may move axially within the sleeve 11. The level at which the connecting members 5 or 5 restrain the electrodes is approximately a simple fraction of the field-height of the precipitator, e.g. the connecting member(s) divide that height into halves or thirds. However it is preferable to offset the level of the member(s) slightly from such exact division since at those places nodes will be expected if any standing waves set up in the electrodes.

This holding of the discharge electrodes at various partial heights of the active electrical field can be used for any big field heights. In these embodiments the discharge electrodes cannot produce vibratory movements at these points because a deformation or vibrating of the lateral guide-frames on which the longitudinal connecting members are fixed, is not possible, even if large field-lengths are concerned, because they are kept rigid by end-frames braced outside the electrical field.

It is furthermore advantageous that the connections of the discharge electrodes with the longitudinal connecting members are executed as gliding connections; an energy-consuming damping will occur here, if vibrations are incited.

The material needed for this manner of holding and connecting the discharge electrodes are insignificantly small compared to the above mentioned known stabilizing designs.

We claim:

1. In an electrostatic precipitator of a type having a plurality of long vertically extending discharge electrodes and a plurality of collecting electrodes arranged in alternating arrays and adapted for gas flow in horizontal directions past the electrodes, with an upper support frame from which the discharge electrodes hang in parallel said arrays and being loaded by tensioning weights at their lower ends, being spaced apart in the arrays by spacing grids at the said lower ends which are rigidly and fixedly spatially related to the upper support frame by end frame structures situated out of the electrical field of the precipitator, there being at least one horizontally extending connecting member at vertical levels which are nearly equal to exact fractions of the lengths of the electrodes so that the said at least one connecting member acts to restrain vibration in the electrodes at positions slightly offset from the nodal positions of standing waves in the electrodes.

2. The improvement claim in claim I wherein the connecting member includes a taut wire woven through the row of electrodes and abutting on alternate sides of the electrodes along the row.

3. The improvement claimed in claim 1 wherein the connecting member bears an insulating guide for each electrode for guiding the said relative vertical displacement.

4. The improvement claimed in claim 3 wherein each said guide is tubular and receives part of the electrode within it each electrode is subdivided along its length into a plurality of discrete parts, the said parts being joined at their adjacent ends in a tube sleeve, the sleeves being respectively received in the said tubular guides.

5. The improvement claimed in claim 1 wherein the at least one connecting member is at at least one level which divides the height of the electrodes into a plurality of approximately equal parts so that the said at least one level is spaced from the nodal position of a standing wave in the electrode.

6. The improvement claimed in claim 1 wherein in an electrostatic precipitator having a plurality of rows of said electrodes at least one said connecting member is provided for each row the connecting members at the same level being spaced by horizontal spacers secured to the end frames.

7. In an electrostatic precipitator having a plurality of long discharge electrodes vertically suspended under tension in an array from an upper carrier frame and having an end frame rigidly associated with the carrier frame beyond each end of the array and out of the electric field of the precipitator, and at least one horizontally extending connecting member secured between the end frames and interacting with each electrode in the array part way along its height, the connecting member being effective against standing wave vibrations in the discharge electrodes induced by the horizontal flow thereagainst of gases the improvement comprising a plurality of discrete, insulating elements strung on the length of a connecting member which is a taut wire woven through the array of electrodes and abutting on alternate sides of adjacent electrodes in the array, whereby the insulating elements restrain the dis charge electrodes against displacement along the horizontal connecting member but permit relative vertical displacement of the electrodes and the connecting member. 

1. In an electrostatic precipitator of a type having a plurality of long vertically extending discharge electrodes and a plurality of collecting electrodes arranged in alternating arrays and adapted for gas flow in horizontal directions past the electrodes, with an upper suppoRt frame from which the discharge electrodes hang in parallel said arrays and being loaded by tensioning weights at their lower ends, being spaced apart in the arrays by spacing grids at the said lower ends which are rigidly and fixedly spatially related to the upper support frame by end frame structures situated out of the electrical field of the precipitator, there being at least one horizontally extending connecting member at vertical levels which are nearly equal to exact fractions of the lengths of the electrodes so that the said at least one connecting member acts to restrain vibration in the electrodes at positions slightly offset from the nodal positions of standing waves in the electrodes.
 2. The improvement claim in claim 1 wherein the connecting member includes a taut wire woven through the row of electrodes and abutting on alternate sides of the electrodes along the row.
 3. The improvement claimed in claim 1 wherein the connecting member bears an insulating guide for each electrode for guiding the said relative vertical displacement.
 4. The improvement claimed in claim 3 wherein each said guide is tubular and receives part of the electrode within it each electrode is subdivided along its length into a plurality of discrete parts, the said parts being joined at their adjacent ends in a tube sleeve, the sleeves being respectively received in the said tubular guides.
 5. The improvement claimed in claim 1 wherein the at least one connecting member is at at least one level which divides the height of the electrodes into a plurality of approximately equal parts so that the said at least one level is spaced from the nodal position of a standing wave in the electrode.
 6. The improvement claimed in claim 1 wherein in an electrostatic precipitator having a plurality of rows of said electrodes at least one said connecting member is provided for each row the connecting members at the same level being spaced by horizontal spacers secured to the end frames.
 7. In an electrostatic precipitator having a plurality of long discharge electrodes vertically suspended under tension in an array from an upper carrier frame and having an end frame rigidly associated with the carrier frame beyond each end of the array and out of the electric field of the precipitator, and at least one horizontally extending connecting member secured between the end frames and interacting with each electrode in the array part way along its height, the connecting member being effective against standing wave vibrations in the discharge electrodes induced by the horizontal flow thereagainst of gases the improvement comprising a plurality of discrete, insulating elements strung on the length of a connecting member which is a taut wire woven through the array of electrodes and abutting on alternate sides of adjacent electrodes in the array, whereby the insulating elements restrain the discharge electrodes against displacement along the horizontal connecting member but permit relative vertical displacement of the electrodes and the connecting member. 